Jennifer Wei Huen Shum

The progress in optic nerve regeneration, where are we？

Optic nerve regeneration is an important area of research. It can be used to treat patients suffering from optic neuropathy and provides insights into the treatment of numerous neurodegenerative diseases. There are many hurdles impeding optic regeneration in mammals. The mammalian central nervous system is non-permissive to regeneration and intrinsically lacks the capacity for axonal regrowth. Any axonal injury also triggers a vicious cycle of apoptosis. Understanding these hurdles provides us with a rough framework to appreciate the essential steps to bring about optic nerve regeneration: enhancing neuronal survival, axon regeneration, remyelination and establishing functional synapses to the original neuronal targets. In this review article, we will go through current potential treatments for optic nerve regeneration, which includes neurotrophic factor provision, inflammatory stimulation, growth inhibition suppression, intracellular signaling modification and modeling of bridging substrates.

Management of Primary Angle-Closure Glaucoma.

AbstractPrimary angle-closure glaucoma (PACG) is a progressive optic nerve degeneration and is defined as a glaucomatous optic neuropathy with associated characteristic enlargement of optic disc cupping and visual field loss that is secondary to ocular hypertension caused by closure of the drainage angle. Angle closure is caused by appositional approximation or adhesion between the iris and the trabecular meshwork. The main treatment strategy for PACG lies in the reduction of intraocular pressure, reopening of the closed angle, and possible prevention of further angle closure. There is no universally agreed best surgical treatment for PACG. Trabeculectomy, goniosynechialysis (GSL), glaucoma implant, and cyclodestructive procedures are effective surgical options. Each of them plays an important role in the management of PACG with its own pros and cons. Accumulating evidence is available to show the effectiveness of visually significant and visually nonsignificant cataract extraction in the treatment of PACG. Trabeculectomy and GSL are often combined with cataract extraction, which may offer additional pressure control benefits to patients with PACG. This review article will discuss laser peripheral iridotomy, argon laser peripheral iridoplasty, and surgeries such as GSL, phacoemulsification, and phaco plus glaucoma surgeries that lower intraocular pressure and also alter the anterior segment and/or drainage angle anatomy. Currently, glaucoma implants and cyclodestruction are mainly reserved for PACG patients who have failed previous filtering operations. Their role as initial surgical treatment for PACG will not be discussed.

Use of anti-vascular endothelial growth factor in the management of pterygium

The rising success of anti‐vascular endothelial growth factor (VEGF) therapies in ocular disease has stimulated the use of such treatments in the surgical management of pterygium. We reviewed the literature to better understand the safety and efficacy of the adjunctive role of anti‐VEGF treatments for pterygium excision. Without surgery, anti‐VEGF alone may favourably alter symptoms and vascularity, but does not cause pterygium regression. Some evidence supports the use of anti‐VEGF as an adjuvant therapy to surgery, especially when using a higher dose and a more frequent dosing regimen. Overall, anti‐VEGF is generally safe and well tolerated in patients with pterygium. Currently, the evidence does not conclusively support the use of anti‐VEGF in pterygium surgery. However, further research may guide unanswered questions regarding the interaction between VEGF and other factors responsible for pterygium growth. In addition, the optimal route and dosage of anti‐VEGF administration is not yet known.

Physical exercise and glaucoma: a review on the roles of physical exercise on intraocular pressure control, ocular blood flow regulation, neuroprotection and glaucoma-related mental health

The benefits of physical exercise on health and well‐being have been studied in a wide range of systemic and ocular diseases, including glaucoma, a progressive optic neuropathy characterized by accelerated apoptosis of retinal ganglion cells (RGCs). Elevated intraocular pressure (IOP) and insufficient ocular perfusion have been postulated to be the two main theories in glaucoma development and progression. The effects of exercise in these two aspects have been demonstrated by numerous researches. A review in 2009 focusing on these two theories concluded that exercise results in transient IOP reduction but an inconsistent elevation in ocular perfusion. However, the majority of the studies had been conducted in healthy subjects. Over the past decade, technological advancement has brought forth new and more detailed evidence regarding the effects of exercise. Moreover, the neuroprotective effect of exercise by upregulation of neurotrophin and enhancement of mitochondrial function has been a focus of interest. Apart from visual impairment, the mental health issues in patients with glaucoma, which include anxiety and depression, should also be addressed. In this review, we mainly focus on publications from the recent years, so as to provide a comprehensive review on the impact of physical exercise on IOP, ocular perfusion, neuroprotection and mental health in patients with glaucoma.

A Case Report: Anti-Psychotic Agents Related Ocular Toxicity.

AbstractChlorpromazine is known to cause ocular pigmentary deposits. However, delayed presentation after cessation of chlorpromazine has not been reported. There are also no reports on whether newer generation of anti-psychotic agents contribute to ocular toxicity. We describe a case of ocular toxicity related to anti-psychotic agents. To the best of our knowledge, this is the first reported case of anterior segment pigmentary deposits associated with olanzapine use, 2 years after the cessation of chlorpromazine.We report a case of ocular toxicity in a patient with history of chlorpromazine usage of 100 mg per day for 13 years and subsequently switched to olanzapine 5 mg for 2 years. There were no signs of ocular toxicity while the patient was on chlorpromazine. However, when the patient switched to olanzapine, she developed the ocular side effect as described for chlorpromazine-induced ocular toxicity, with pigmentary depositions on both corneas and the anterior lens surface and decrease in vision.Olanzapine, a newer anti-psychotic agent, may play a role in the ocular pigmentary deposition, either directly causing pigmentary deposition itself or accentuating the effect of chlorpromazine as the 2 drugs act on the same receptors, although further studies are required to support this hypothesis. As patients with psychiatric conditions may not voluntarily complain of visual symptoms, ocular screening could be considered in these patients receiving chronic anti-psychotic treatment, so that any ocular toxicity could be diagnosed in a timely manner.

Development and pilot-testing of patient decision aid for use among Chinese patients with primary open-angle glaucoma

Background A patient decision aid (PDA) is a tool for shared decision making (SDM), which emphasises patient empowerment. It is useful in chronic diseases and when there are multiple, no best single treatment option. Although SDM is prevalent in Western countries, its use is limited in Chinese societies, where the adoption of a paternalistic approach is strong. Here, we report the development, acceptance and pilot test results of a PDA targeted at Chinese patients with primary open-angle glaucoma (POAG). Methods We developed a PDA designed for use in Chinese patients with POAG. Recruited subjects were given our PDA. Baseline evaluation included decision conflict scale (DCS), validated glaucoma adherence questionnaires and glaucoma knowledge questionnaire. Subjects were briefed through the PDA and instructed to read it that day. Three to four weeks later, follow-up questionnaire as described above were conducted with the addition of acceptance questionnaires. Results Data from 65 subjects were available. The PDA was well received among subjects. DCS improved from 48.9±20.4 at baseline to 34.3±20.3 during follow-up, with P<0.01. Validated medication adherence questionnaires and knowledge showed improvement from baseline, which was statistically significant. Conclusions The use of PDA among Chinese subjects with POAG demonstrated positive reception and acceptance. Evaluation of its initial effects shows improvement in DCS, medication adherence and glaucoma knowledge. The implementation of SDM and PDA among Chinese subjects with POAG is encouraged. Future studies with randomised design and later evaluation time points can further reveal the impacts of PDA among Chinese subjects with POAG.

Suprachoroidal Hemorrhage with Delayed Rebleeding as the First Presentation of Bullous Pemphigoid Associated Acquired Hemophilia

We report a case of phacoemulsification conversion complicated by suprachoroidal haemorrhage (SCH) and delayed rebleeding at day 5 postoperation, as the first presentation of bullous pemphigoid associated acquired hemophilia. This association has been reported sparingly in the past, and almost exclusively only in hematology literature. To the best of our knowledge, this is the first case of delayed SCH rebleed presenting in a patient with previously undiagnosed Acquired Hemophilia reported. Although exceedingly rare, acquired hemophilia leads to drastic complications and has a high mortality rate. Advice to allow early recognition and prevention of complications is summarized.

Intraocular pressure elevation in the contralateral untreated eye following selective laser trabeculoplasty in rabbit eyes

Our study aimed at evaluating if a single session of unilateral selective laser trabeculoplasty would affect the intraocular pressure of the fellow untreated eye in rabbits. Eleven rabbits were involved. 360° selective laser trabeculoplasty with 532 nm frequency-doubled green Nd:YAG laser was performed over the right eyes. The mean intraocular pressure of both eyes at baseline, 3 hours, 24 hours, 3 days and 7 days after laser were measured. The baseline mean intraocular pressure of the right eye and the left eye were 8.07 ± 1.72 mmHg and 8.27 ± 1.56 mmHg respectively (p=0.78). The mean intraocular pressure of the treated eye was lower than the baseline from 3 hours through 3 days after laser, with a maximum mean decrease of 1.36 mmHg on Day 3. On the contrary, the mean intraocular pressures of the untreated eyes were higher than the baseline throughout the study, particularly at later course (1.91 mmHg on Day 3 and 1.85 mmHg on Day 7). This suggests the change of intraocular pressure in one eye after selective laser trabeculoplasty, leads to a change in the pressure of the fellow eye. It is thought that a neuronal and humoral response is triggered centrally after unilateral intraocular pressure change. The detailed mechanisms would require further studies to evaluate. The rising intraocular pressure trend in the contralateral untreated eye suggests that response may continue to exert its action for some time after the initial laser. This is the first reported study of intraocular pressure elevation of the untreated eye following contralateral selective laser trabeculoplasty.